Use Pesticides Wisely to Avoid Resistance

Thursday May 08, 2025

Repeated use of pesticides with the same mode-of-action used in the orchard can accelerate the development of insecticide resistance. WSU recommends that when you choose insecticides, keep track of which ones are being used so that you alternate materials with the different modes-of-action (shown in DAS) between generations.

Bt Applications for Leafrollers

Thursday May 08, 2025

Bacillus thuringiensis (Bt) is a bacterium that must be eaten by lepidopteran larvae (caterpillars) to be effective. Bt is a great material for leafroller control because it is specific and has little effect on natural enemies. However, it must be applied 2-3 times to be effective when leafroller populations are high. Experience has also shown that in the spring, the high temperatures need to be above 65°F for 3 or more days so that larvae have a chance to feed on it before sunlight breaks it down. DAS provides forecast temperatures for all stations in the "Weather Forecast" and in the "Show Data Grid" table so that you can decide whether or not to use Bt or other recommended chemicals.

Campylomma Bug

Thursday May 01, 2025

Campylomma can be a pest during the bloom period when it feeds on young developing fruit. However, it is a beneficial predaceous insect that is valuable in control of soft bodied insects (such as spider mites) throughout the rest of year. DAS predicts the phenology of Campylomma during the spring, but beating tray samples need to be taken before and during the spring bloom period to determine if Campylomma is present and whether treatment is necessary.

Preserving Biocontrol Agents

Tuesday Apr 22, 2025

Natural enemies (NE) are crucial to the long-term stability of management programs. Pesticides need to be chosen not only on the basis of efficacy against the pests, but also by minimizing their effect on natural enemies. DAS provides both the effects on pests and on the key natural enemies.

Leafroller and Codling Moth Movement During the Season

Tuesday Apr 22, 2025

Movement of codling moth and leafrollers into your orchard can be the start of serious damage. Both CM and leafrollers can easily fly 5-7 miles in a single night and their reproduction is as high as those that do not fly. Although 5-7 mile flights are common, the likelihood of the moths coming to your orchard in high numbers is directly related to wind speed, distance from the source, and the environment in between the source and your orchard.